1. Field of the Invention
This invention relates to a device for cleaning or polishing a roll, and applies in particular to the cleaning of rolling mill rolls.
2. Technological Background
During the rolling of metal strip, the working surfaces of the rolls in direct or indirect contact with the rolled product have to be cleaned in order to ensure the quality of the surface state. This is particularly true in the case of hot-rolling aluminum.
The cleaning is performed by a tool applied to the working surface of the roll to be cleaned. This tool can advantageously comprise a rotary brush in the form of a brush roller mounted for rotation about an axis parallel to the generating lines of the roll to be cleaned, and an associated driving device which is able to apply rotary torque to at least one end of the brush roller.
A rolling mill generally comprises two working rolls placed on either side of the feed path of the product to be rolled, and at least two back-up rolls which the sides of the working rolls opposite to the feed path bear against, a clamping force being applied between the pressure rolls. The diameter of the working rolls is relatively small, and thus the cleaning device must be passed into a fairly restricted space delimited by the columns of the stand, the product being rolled and the pressure roll(s). The cleaning device is therefore normally mounted on a support that can move inside this space between a position in which the brush roller is applied against the roll to be cleaned and a retracted position used, for example, when starting up the mill or carrying out maintenance operations.
Many cleaning devices have been suggested for this purpose.
The brush roller is often mounted in rotary fashion on a support device comprising two parallel arms, the free ends of which are fitted with centering brush roller centering bearings. The arms are mounted on a chassis which can slide in a plane parallel to the axis of the brush roller between a brush roller application position and a retracted position. Moreover, to provide better access to the roll, the device supporting the brush roller can advantageously be made to pivot about a fixed axis in order to move it to a rest position away from the rolling mill rolls (DE-A-1.959.806).
According to another known arrangement, the brush roller support device is mounted on a set of articulated arms forming a deformable parallelogram (DE-A-1.943.847).
The means that drive the brush roller in rotation must be able to follow the movements of the support device. The brush roller can, for example, be associated with at least one driving wheel wedged on one of its ends, and connected by a chain to a rotation control wheel mounted on the support and which moves with the support (DE-A-1.959,806). In this case, the motor torque must be transmitted, for example, via an elongation piece fitted with a universal joint so that the movements of the support can be followed (DE-A-1.959,806). The rotation control device may also be fixed, but this requires the use of a Galle chain and means for maintaining its tension, since the length of the kinematic chain that connects the rotation control device to the shaft of the brush roller will vary according to its position (DE-A-1.943.847).
Moreover, to ensure proper cleaning and avoid scratches forming on the roll, the brush roller must also be subject to a "to-and-fro" type axial movement parallel to the axis of the roll in order to correctly distribute the brushing effect over the whole surface of the roll (FR-4-1.463.503).
In view of all the problems to be overcome, devices of the prior art are fairly complex and bulky.
The brush roller or roll often needs to be removed, and, given the mechanical complexity of the cleaning assemblies, this implies numerous relatively long and costly dismantling operations.
Moreover, development in rolling techniques is leading to a whole array of auxiliary devices being associated with the rolling mill, designed for example to compensate for deformation and adjust the distribution of stresses applied to the product, and all of these reduce the space in which the cleaning device can be placed.